Hi everybody
I have recently built a 176 vari mu compressor clone using Sowter 1285 output transformer. They offer this model specifically for the 176 compressor, like the original it has primary taps for the different ratio settings.
The compressor seems to be operating as intended and it sounds very nice, however I am concerned about the threshold points at the different ratio settings.
Basically the 12:1 and 8:1 settings have a much higher threshold point than the 2:1 and 4:1 settings.
12:1 in particular is not very useful, because the threshold point is way above the point where the amplifier starts clipping.
I have managed to alter the threshold points by changing the resistors on the ratio switch - R39 for 12:1 and R45 for 8:1
Smaller resistors lower the threshold voltage, so the different ratio settings operate at similar threshold points.
I don't understand why the stock resistor values don't really work in my build. Maybe the Sowter 1285 is not exactly a drop in replacement and it actually requires some tweaks to the original circuit ?
I have recently built a 176 vari mu compressor clone using Sowter 1285 output transformer. They offer this model specifically for the 176 compressor, like the original it has primary taps for the different ratio settings.
The compressor seems to be operating as intended and it sounds very nice, however I am concerned about the threshold points at the different ratio settings.
Basically the 12:1 and 8:1 settings have a much higher threshold point than the 2:1 and 4:1 settings.
12:1 in particular is not very useful, because the threshold point is way above the point where the amplifier starts clipping.
I have managed to alter the threshold points by changing the resistors on the ratio switch - R39 for 12:1 and R45 for 8:1
Smaller resistors lower the threshold voltage, so the different ratio settings operate at similar threshold points.
I don't understand why the stock resistor values don't really work in my build. Maybe the Sowter 1285 is not exactly a drop in replacement and it actually requires some tweaks to the original circuit ?